DS1258Y Datasheet, PDF (1/8 Pages) Dallas Semiconductor – 128k x 16 Nonvolatile SRAM

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FEATURES
§ 10-Year Minimum Data Retention in the
Absence of External Power
§ Data is Automatically Protected During a
Power Loss
§ Separate Upper Byte and Lower Byte Chip-
Select Inputs
§ Unlimited Write Cycles
§ Low-Power CMOS
§ Read and Write Access Times as Fast as 70ns
§ Lithium Energy Source is Electrically
Disconnected to Retain Freshness Until
Power is Applied for the First Time
§ Full ±10% Operating Range (DS1258Y)
§ Optional ±5% Operating Range (DS1258AB)
§ Optional Industrial Temperature Range of
-40°C to +85°C, Designated IND
DS1258Y/AB
128k x 16 Nonvolatile SRAM
PIN ASSIGNMENT
CEU 1
CEL 2
DQ15 3
DQ14 4
DQ13 5
DQ12 6
DQ11 7
DQ10 8
DQ9 9
DQ8 10
GND 11
DQ7 ¹²
DQ6 ¹³
DQ5 14
DQ4 15
DQ3 16
DQ2 ¹⁷
DQ1 18
DQ0 19
OE 20
40
VCC
39 WE
38 A16
37 A15
36 A14
35 A13
34 A12
33 A11
32 ^A10
31 A9
30 GND
29 A8
28 A7
27 A6
26 A5
25 A4
24 A3
23 A2
22 A1
21 A0
40-Pin Encapsulated Package
740mil Extended
PIN DESCRIPTION
A0 to A16
- Address Inputs
DQ0 to DQ15
- Data In/Data Out
CEU
- Chip Enable Upper Byte
CEL
- Chip Enable Lower Byte
WE
- Write Enable
OE
- Output Enable
V_CC
GND
- Power (+5V)
- Ground
DESCRIPTION
The DS1258 128k x 16 nonvolatile (NV) SRAMs are 2,097,152-bit fully static, NV SRAMs, organized as
131,072 words by 16 bits. Each NV SRAM has a self-contained lithium energy source and control
circuitry that constantly monitors V_CC for an out-of-tolerance condition. When such a condition occurs,
the lithium energy source is automatically switched on and write protection is unconditionally enabled to
prevent data corruption. DIP-package DS1258 devices can be used in place of solutions that build NV
128k x 16 memory by utilizing a variety of discrete components. There is no limit on the number of write
cycles that can be executed and no additional support circuitry is required for microprocessor interfacing.
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